#include <stdio.h>
#include <ctype.h>
#define N 15
int main(void)
{
    char numbers[N] = {};
    printf("Enter phone number: ");
    char ch;
    for (int i = 0; i < N, ((ch = getchar()) != '\n'); i++)
        numbers[i] = ch;
    printf("In numeric form: ");
    for (int i = 0; i < N; i++) {
        if (numbers[i] == '\0')
            break;
        switch (numbers[i])
        {
        case 'A': case 'B': case 'C':
            printf("2");
            break;
        case 'D': case 'E': case 'F':
            printf("3");
            break;
        case 'G': case 'H': case 'I':
            printf("4");
            break;
        case 'J': case 'K': case 'L':
            printf("5");
            break;
        case 'M': case 'N': case 'O':
            printf("6");
            break;
        case 'P': case 'Q': case 'R': case 'S':
            printf("7");
            break;
        case 'T': case 'U': case 'V':
            printf("8");
            break;
        case 'W': case 'X': case 'Y': case 'Z':
            printf("9");
            break;
        default:
            printf("%c", numbers[i]);
            break;
        }
    }
    printf("\n");
    return 0;
}